Abstract C082: A case of intracranial myeloid sarcoma discovered after a subdural hematoma

Abstract Acute myeloid leukemia (AML) is a heterogeneous disorder characterized by the proliferation of myeloid progenitor cells infiltrating the bone marrow. Myeloid sarcoma is an extramedullary malignancy that can occur in soft tissue, bone, lymph nodes however CNS involvement is rare. 68-year-old female with past medical history of breast cancer s/p left-sided mastectomy in 2014 and tamoxifen therapy for seven years that presented to the ED for altered mental status, and headache that was ongoing for the past several days with associated significant weight loss, and easy bruising. CT brain revealed stable late subacute to chronic bilateral subdural hematomas with small area of more recent hemorrhage on the left; left to right shift of 2mm noted. MRI brain revealed bilateral subdural fluid collection; mass effect from larger left collection resulting in rightward midline shift of 3mm. Significant labs was noted for a leukocytosis 73,000, normochromic normocytic anemia, thrombocytopenia, and elevation of immature cells of promyelocytes myelocytes, metamyelocytes, and blasts. Flow cytometry revealed leukocytosis with blasts greater than 40% consistent with AML. Bone marrow aspirate revealed AML, non-M3. Molecular genetics revealed FLT3-ITD negative. Cytogenetics revealed abnormal karyotype with Trisomy 8. Over the patient’s hospital course, the patient became progressively obtunded. Repeat imaging showed stable size of bilateral subdural hemorrhages with a stable mass effect but increased cerebral edema and crowding of the basilar cisterns. Neurosurgery emergently performed a right parietal burr hole with evacuation of the chronic subdural hematoma and placement of a subdural drain. During the procedure, a left parietal craniotomy had to also be performed after an extra-axial parietal mass was incidentally found. Pathology of the brain mass revealed acute myeloid leukemia. The patient was transferred to a tertiary care center for plans of induction chemotherapy. Intracranial myeloid sarcoma is a rare manifestation of AML with an incidence of 0.4%. Oftentimes intracranial myeloid sarcoma is detected during routine CT/MRI studies given acute neurological symptoms. However in our case, initial imaging showed the acute subdural hematomas, and the mass was found incidentally during surgery. Risk factors associated with AML include genetic disorders such as Trisomy 8 which is found from cytogenetic testing. Trisomy 8 is one of the most common cytogenetic alterations found in patients’s with AML due to the association with mutations in DNA methylation causing a stronger predisposition to the pathogenesis of leukemia with a reported frequency noted to be between 10-15%. It has been noted that the prognosis of Trisomy 8 with AML has a shorter median overall survival, and is classified as an intermediate risk AML. Treatment includes surgical intervention to relieve the mass effect, and also aides with the histopathologic diagnosis. In addition the use of adjuvant radiotherapy or chemotherapy significantly reduced mortality. Citation Format: Bianca Vahia, Ram Hirpara, Danilo Frias, Ahmed Behairy. A case of intracranial myeloid sarcoma discovered after a subdural hematoma [abstract]. In: Proceedings of the 18th AACR Conference on the Science of Cancer Health Disparities; 2025 Sep 18-21; Baltimore, MD. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2025;34(9 Suppl):Abstract nr C082.